Apparatus for heating oil wells



P V DOWNEY ET AL APPARATUS FOR HEATING OIL WELLS Filed March 26, 1927 Aug. 21, 1928.

gmm rflow 74inch? y 1902127261 Patented Aug. 21, 1928.

1,681,523 PATENT OFFICE.

PATRICK V. DOWNEY AND CLIFFORD H. WEN DROFF, 01'' DENVER, COLORADO.

APPARATUS FOR HEATING OIL WELLS.

Application filed March 26, 1927.

This invention relates to improvements in devices for heating the interior of oil wells.

It is well known that many oil wells become unproductive because the paraffin contained in the oil solidifies and seals the pores through which the oil enters the well. In order to bring these wells'back to productiveness, it is necessary to remove the paraflin seal from the walls of the well so that the oil from the surrounding soil can enter. As paraflin will melt at a very moderate degree of heat, many attempts have been made to introduce a suiiicient quantity of heat into the wells to liquefy the parafiin to such an extent that can be removed by pumping. A No attempt will be made to review the prlor art except to state that many of the proposed methods have failed became they required too complicated an apparatus and were too expensive. I

It is the object of this invention to produce an apparatus of very simple construction that can be installed in the well without making it necessary to withdraw the pump line and which can be left in position as long as the well is productive.

Another object of this invention is to produce an apparatus in which the heat is generated by means of an electric current and which, in addition to heating the lower end of the well, will also heat the pump line so that the molten paraffin will not solidify within the pump pipes and render the pump in-' operative.

The above and other objects that may be come apparent as this description proceeds are obtained by means of an arrangement and combination of parts that will now be described in detail, and reference for this purpose will now be had to the accompanylng drawing in which the invention has been illustrated and in which:

F ig. 1 is a section through a well showing my device in place therein;

Fig. 2 is a section taken on line 22, Fig. 1; and r Fig. 3 is a section taken on line 3-3, Fig. 1.

Numeral 1 represents the surface of the ground and 2 the casing wit-l1 which the well is lined. The well has been shown as terminating in a sump 3 through the wall 4 of which the oil enters. The ordinary pump line is represented by 5; this terminates in a strainer 6 located near the bottom of the sump. The

casing has been shown as of the same diame- Serial N 0. 178,679.

through the former of which the pipe 5 extends. A collar 13 is secured to the pipe 5 and rests on the upper surface of the plate from which the pump line is supported.

Through opening 12, the pipe 14 of the heating apparatus extends. Pipe 14, like pipe 5, is provided with a collar 15 that is clamped to it by means of a set screw 16 and extends downwardly to a point near the bottom of the sump where it terminates in a conical cap 17. A T 18 is secured to the upper end of pipe 14. A connector 19 extends from the upper end of the T and secured to this is a cap 20, which has a central opening 21. An insulating bushing 22 extends through the opening in the cap and is provided with anopening for the reception of the pipe 23. A collar 24 is secured to the pipe 23 by means of a set screw 25. Pipe 23 extends almost the entire length of pipe 14 and terminates near the bottom thereof in a coupling 26. Wherever the pipe 23 is provided with a coupling, it is also provided with an insulating ring 27 that serves to hold it properly spaced within the pipe 14. Heating elements consisting of tubular spools 28 about which is wound a coil of highly refractory resistance wire 29 are threaded onto pipe 23 and spaced therealong.

Clamps 30 are secured to the pipes directly below each one of the spools 28 and support the latter. One end of the wire 29 is elect-rically connected with the clamp 30 and is 7 therefore electrically connected with pipe 23 which serves as one conductor of the electric circuit. The other ends of coils 29 are connected in parallel to an asbestos coveredinsulating conductor 31. A conductor "32 extends from the upper end of pipe 23 to the switch 33.

A centrifugal fan 34 has its intake port connected to the side opening in the T 18 by means of a pipe 35 and has its outlet port connected tothe upper end of the pipe 23 by means of a flexible tube 36. An electric motor 37 is di rectly connected with fan 34. The drawing shows a generator G which represents, broadly, a sourceoflcurrcnt, and a controller R by in'parallel and are therefore independent of one another so that if one should burn out the others will still function.

\Vhen the heater is in use current is permitted to flow through the coils of the heating elements so as to generate heat. Since these coils are located within a closed pipe, the interior of the pipe very soon becomes very hot and'some of this heat is transmitted to the material of pipe 14 which thereby becomes heated. In order to distribute the heat along the entire length of the pipe the fan 34 is provided. I This fan sucks the air from the top of pipe 14 and blows it down through pipe 23 thereby producing an air current that travels upwardly-along the interior of pipe 14. This current of air need not be very strong but should be sufficient to prevent the formation of points of excessively high temperature.

The greater number of heating elements may be located near the bottom of pipe 1% and therefore the greater amount of heat will be generated there than at any other point. The heat from the pipe 14: will raise the tear perature of the interior of the well so as to cause the parafiin to melt. Since the heater extends parallel with the pump line the latter will be heated and can be maintained at a temperature above that of the melting point of paratfin so that the latter will not solidify on the interior of the pump line, while it is being removed from the well.

Special attention is called to the feature 05 circulating air through the interior of the heater pipe. Since the same air is continual- 1y circulated, there will be no appreciable loss of heat due to this, but the motion of the air will distribute the heat uniformly along the interior of the pipe. The idea of heating the pump line throughout its entire length is also believed to .be new.

Since the heating elements are all contained within pipe 14, that is an ordinary two-inch pipe, the heater can be put in place without removing the pump and can be retained as long as necessary.

This application is continuation, in part, of application Serial Number 161,121, filed January 14, 1927.

Having thus described the invention what is claimed as new is:

1. An apparatus for heating oil wells, com prising, in combination, a pipe adapted to extend from the top of the well to the bottom thereof, a pipe of smaller diameter located within the first pipe and extending substantially from one end thereof to the other, a plurality of electric heater elements secured to the smaller pipe and spaced from each other, means for conducting an electric current t the hea i g elements, and means for causing a current of air to flow downwardly through the smaller pipe and upwardl within the larger pipe whereby the electric eaters will be subjected to a flow of air that tends to distribute the heat.

2. An apparatus for heating oil wells, comprising, in combination, a pipe havin its lower end closed and adapted to extend rom the top to the bottom of a well, a smaller pipe located within the first mentioned pipe electric heating elements secured to the outslde of the smaller pipe and spaced therealong, means for conducting an electric current to the heating elements and means for circulating air in one direction through the smaller pipe and in the opposite direction through the annular space between the pipes.

3. An apparatus for heating oil wells, comprising, in combination, a pipe having its lower end closed and adapted to extend from the top to the bottom of a well, a smaller pipe located within the first mentioned pipe, electric heating elements secured to the outside of the smaller pipe and spaced therealong, means for conducting an electric currentto the heating elements, insulators secured to the smaller pipe for holding it centered in the larger pipe and means comprising a pump for causing a current of air to flow in one direction through the smaller pipe and in the opposite direction through the larger pipe.

. 4. An apparatus for heating the interior of an oil well comprising, in combination, a pipe extending from the top of the well to a point near its bottom, means for closing both ends of said pipe, a pipe of smaller diameter pas ing through the upper end closure and extending downwardly to a point near the bottom closure of the first pipe, a plurality of electric heating elements secured to the smaller pipe, means for conducting an electric current to the heaters and means for causing the air dthin said pipes to circulate.

5. An apparatus for heating the interior of an oil well comprising, in combination, a pipe extending from the top of the well to a point near its bottom, means for closing both ends of said pipe, a pipe of smaller diameter passing through the upper end closure and extending downwardly to a point near the bottom closure of the first pipe, a plurality of electric heating elements secured to the smaller pipe, means for conducting an electric current to the heaters and means for causing the air within said pipes to circulate, said last named means comprising an air pump having its intake port connected with the annular space between the pipes near the top of the outer pipe and having its delivery port connected with the upper end of the smaller pipe.

In testimony whereof we afiix our signa- PATRICK V. DOWNEY. CLIFFORD H. WENDROFF, 

